Copolymers of carboxylic acids and quaternary ammonium compounds and the use thereof as thickeners of dispersants

ABSTRACT

A copolymer obtainable by free-radical polymerization of 
     A) 50-99.99% by weight of an olefinically unsaturated C 3 -C 5  monocarboxylic acid, of an olefinically unsaturated C 4 -C 8  dicarboxylic acid or the anhydride thereof or a mixture of such carboxylic acids or anhydrides with 
     B) 0.01-50% by weight of an olefinically unsaturated quaternary ammonium compound of the formula I or II                    
      where 
     R 1  is C 6 -C 20 -alkyl, C 6 -C 20 -alkenyl, C 5 -C 8 -cycloalkyl, phenyl, phenyl(C 1 -C 12 -alkyl) or (C 1 -C 12 -alkyl)phenyl, 
     R 2  is hydrogen, methyl or phenyl, 
     R 3  and R 4  are each H or C 1 -C 4 -alkyl, 
     X is halogen, C 1 -C 4 -alkoxysulfonyloxy or C 1 -C 4 -alkanesulfonate, it also being possible for the latter to occur as R 3  or R 4  with the formation of a betaine structure, 
     Y is O or NH, and 
     A is C 1 -C 6 -alkylene, or a mixture of such ammonium compounds, 
     C) 0 to 49.99% by weight of an acrylate or methacrylate of the formula III                    
      where R 1 , R 2  and Y have the abovementioned meanings, R 5  is hydrogen, methyl or ethyl, and n is a number from 0 to 25, 
     D) 0-49.99% by weight of other copolymerizable monomers and 
     E) 0-5% by weight of one or more compounds with at least two olefinically unsaturated groups in the molecule as crosslinker. The copolymers are suitable as thickeners and dispersants, especially in cosmetic compositions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel copolymers of carboxylic acidsand quaternary ammonium compounds, with or without acrylates ormethacrylates, other copolymerizable monomers and crosslinkers. Thepresent invention also relates to the use of these copolymers asthickeners or dispersants, in particular in cosmetic compositions, andto cosmetic compositions containing these copolymers.

2. Description of the Related Art

Thickeners or viscosity regulators conventionally used are copolymers ofolefinically unsaturated carboxylic acids such as (meth)acrylic acid,maleic acid or maleic anhydride and hydrophobic comonomers such asesters of (meth)acrylic acid with or without small amounts of acrosslinker. Copolymers of this type are described, for example, in EP-A328 725 (1) and EP-A 435 006 (2). Polymers of this type may occasionallybe used as emulsifying components in water/oil mixtures. The polymersexert their thickening action once a considerable part of the acidfunctionality has been neutralized with a suitable base; they are thenin the form of a polyanion.

Polymers of this type have some disadvantages. Since the hydrophobiccomonomer is generally insoluble in water, the polymers must often besynthesized in an organic solvent. Solvents of this type are often ahealth hazard or even toxic. The content of hydrophobic comonomer makesthese polymers generally dispersible in water only with difficulty.Furthermore, it is occasionally necessary to use very large amounts ofthe hydrophobic comonomer. Another disadvantage is that the stability toelectrolytes is often low.

Polymers which have a large number of cationic groups are said likewiseto be utilizable as thickeners or dispersants. Polymers of this typehave a high affinity for the dispersed substances whose surfaces usuallyhave a negative charge. Cationic polymers may therefore frequently havethe opposite effect and lead to coalescence of existing dispersions;they are therefore also preferably used as flocculants.

DE-B 11 08 436 (3) describes copolymers of ethylenically unsaturatedcompounds which are sparingly soluble in water, eg. esters ofunsaturated carboxylic acids, and N- or C-vinyl-substituted aromaticcompounds which contain a quaternary N atom, eg.N-vinyl-N′-benzyl-imidazolium chloride. The substances are recommendedfor the finishing of textiles and for producing films and coatings.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide novel polymers asthickeners and dispersants, specifically for cosmetic compositions,which no longer have the disadvantages of the prior art agents.

We have found that this object is achieved by a copolymer obtainable byfree-radical polymerization of

A) 50-99.99% by weight of an olefinically unsaturated C₃-C₅monocarboxylic acid, of an olefinically unsaturated C₄-C₈ dicarboxylicacid or the anhydride thereof or a mixture of such carboxylic acids oranhydrides with

B) 0.01-50% by weight of an olefinically unsaturated quaternary ammoniumcompound of the formula I or II

 where

R¹ is C₆-C₂₀-alkyl, C₆-C₂₀-alkenyl, C₅-C₈-cycloalkyl, phenyl,phenyl(C₁-C₁₂-alkyl) or (C₁-C,₁₂-alkyl)phenyl,

R² is hydrogen, methyl or phenyl,

R³ and R⁴ are each H or C₁-C₄-alkyl,

X is halogen, C₁-C₄-alkoxysulfonyloxy or C₁-C₄-alkane-sulfonate, it alsobeing possible for the latter to occur as R³ or R⁴ with the formation ofa betaine structure,

Y is O or NH, and

A is C₁-C₆-alkylene, or a mixture of such ammonium compounds,

C) 0 to 49.99% by weight of an acrylate or methacrylate of the formulaIII

 where R¹, R² and Y have the abovementioned meanings, R⁵ is hydrogen,methyl or ethyl, and n is a number from 0 to 25,

D) 0-49.99% by weight of other copolymerizable monomers and

E) 0-5% by weight of one or more compounds with at least twoolefinically unsaturated groups in the molecule as crosslinker.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a preferred embodiment, the copolymer according to the invention iscomposed of

A) 70-99.85% by weight of the carboxylic acid component A,

B) 0.1-29.95% by weight of the quaternary ammonium compound I or II,

C) 0-29.85% by weight of the acrylate or methacrylate III,

D) 0-29.85% by weight of other copolymerizable monomers and

E) 0.05-2% by weight of the crosslinker component E.

Particularly suitable as component A are acrylic acid, methacrylic acidand maleic anhydride, as well as crotonic acid, 2-pentenoic acid, maleicacid, fumaric acid or itaconic acid.

Suitable for R¹ in the quaternary ammonium compounds I or II ofcomponent B are C₆-C₂₀-alkyl, especially C₁₂-C₁₈-alkyl, eg. n-hexyl,n-octyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl, n-undecyl, n-dodecyl,n-tridecyl, isotridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl,n-heptadecyl, n-octadecyl or n-eicosyl, C₆-C₂₀-alkenyl, especiallyC₁₂-C₁₈-alkenyl, eg. oleyl, linolyl or linolenyl, C₅-C₈-cycloalkyl, eg.cyclopentyl, cyclohexyl, methylcyclohexyl or dimethylcyclohexyl, phenyl,phenyl(C₁-C₁₂-alkyl), especially phenyl(C₁-C₄-alkyl), eg. 2-phenylethyl,3-phenylpropyl, 4-phenylbutyl or, in particular, benzyl, or(C₁-C₁₂-alkyl)phenyl, especially (C₁-C₉-alkyl)phenyl, eg. n-nonylphenyl,n-octylphenyl or o-, m- or p-tolyl.

R² in the compounds I or II is preferably hydrogen or methyl.

R³ and R⁴ in compound II are each preferably C₁-C₃-alkyl, ie. methyl,ethyl, n-propyl or isopropyl.

The anion X is halogen, especially chlorine or bromine, as well asiodine, C₁-C₄-alkoxysulfonyloxy, especially C₁-C₃-alkoxysulfonyloxy, inparticular methoxysulfonyloxy or ethoxysulfonyloxy,C₁-C₄-alkanesulfonate, especially C₁-C₃-alkanesulfonate, in particularmethanesulfonate or ethanesulfonate, or C₁-C₄-alkanesulfonate, inparticular C₁-C₃-alkanesulfonate, which occurs as R³ or R⁴ withformation of a betaine structure, eg. 3-sulfopropyl.

The alkylene bridge A is preferably a straight-chain or branched C₂-C₄bridge, eg. 1,2-ethylene, 1,3-propylene, 1,2-propylene, 2,3-butylene or1,4-butylene, as well as pentamethylene or hexamethylene.

Quaternary ammonium compounds I or II which are very particularlypreferred as component B are those where

R¹ is C₁₂-C₁₈-alkyl, C₁₂-C₁₈-alkenyl, or benzyl,

R² is hydrogen, methyl or phenyl,

R³ and R⁴ are each C₁-C₄-alkyl,

X is chlorine, bromine, methoxysulfonyloxy, ethoxysulfonyloxy,methanesulfonate, ethanesulfonate or C₁-C₃-alkanesulfonate, which occursas R³ or R⁴ with formation of a betaine structure,

Y is O or NH, and

A is C₂-C₄-alkylene.

Particularly suitable as acrylates or methacrylates II for component Care stearyl acrylate, stearyl methacrylate, N-stearylacrylamide,N-stearylmethacrylamide, cetyl acrylate, cetyl methacrylate, laurylacrylate, lauryl methacrylate, myristyl (meth)acrylate, behenylacrylate, behenyl methacrylate or mixtures thereof. If the intention isto use (meth)acrylates or (meth)acrylamides III reacted with ethyleneoxide, propylene oxide or butylene oxide, the degree of alkoxylation nis preferably from 3 to 25.

Examples of other copolymerizable monomers D which are suitable areN-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, C₁-C₆-alkyl(meth)acrylates, eg. methyl (meth)acrylate or ethyl (meth)acrylate, oraminoalkyl (meth)acrylates or aminoalkyl (meth)acrylamides of theformula IV

where R², R³, R⁴, Y and A have the abovementioned meanings.

The crosslinker component E is either a watersoluble compound such asdivinylethyleneurea, bisacrylamidoacetic acid, methylenebisacrylamide,diallyltartaramide or (meth)acrylic esters of polyethylene glycols, forexample tetraethylene glycol diacrylate or a water-insoluble compoundsuch as ethylene glycol di(meth)acrylate, divinylbenzene, allylmethacrylate, trivinylcyclohexane, an aliphatic non-conjugated dieneand, in particular, an allyl ether of trimethylolpropane, ofpentaerythritol or of sucrose with at least two allyl ether units permolecule. Pentaerythritol triallyl ether, oleyl methacrylate,diallyltartaramide, bisacrylamidoacetic acid, methylenebisacrylamide or(meth)acrylic esters of polyethylene glycols are particularly preferred.

The preparation of the quaternary ammonium compounds I or II is known inprinciple or can be carried out in a similar way to known preparationmethods. The preparation is carried out preferably by reacting anamine-functionalized (meth)acrylate or (meth)acrylamide and anN-vinylimidazole derivative, preferably N-vinylimidazole, with, forexample, a long-chain alkyl halide at elevated temperature, if requiredin a suitable solvent which is, if required, removed after the reactionis complete, or in bulk. If required, the monomers B can be purified,for example, by reprecipitation or recrystallization from suitablesolvent mixtures.

The appropriate organic halides, especially longchain alkyl chlorides,are reacted with N-vinylimidazole or with aminoalkyl (meth)acrylates oraminoalkyl (meth)acrylamides, preferably in polar solvents which areable to take on more than 0.5% by weight of water at room temperature.Examples of solvents of this type are alcohols, eg. ethanol, n-butanol,n-amyl alcohol or isopropanol, ketones such as acetone or methyl ethylketone, amides, eg. dimethylformamide, dimethylacetamide orN-methylpyrrolidone, nitriles such as acetonitrile, nitro compounds suchas nitromethane or nitroethane, and glycol ethers, eg. ethylene glycolmonomethyl ether or diethylene glycol dimethyl ether, sulfur compoundssuch as dimethyl sulfoxide or sulfolane, carbonates such as propylenecarbonate or diethylene carbonate and esters such as ethyl acetate.Mixtures of these solvents can likewise be used. When the resultingproducts are soluble in the relevant media, it is also possible to usewater or mixtures of water with the solvents described. Reactiontemperatures above 40° C. are generally beneficial. To reach highertemperatures it is expedient in many cases to apply pressures up to 30bar. The reaction can also be catalyzed by adding small amounts of aniodide or bromide.

The reaction can be carried out in the presence of approximatelyequimolar amounts of the alkylating agent. However, for the subsequentreaction to polymers it is often unnecessary to achieve completealkylation. The reaction can therefore also be carried out in thepresence of less than stoichiometric amounts of the alkylating agent. Onthe other hand, to achieve maximum degrees of alkylation, it is oftenexpedient to carry out the reaction in the presence of an up to 4-foldexcess of the alkylating agent. In this case, the excess alkylatingagent is often removed from the product by a purification step.

The resulting compounds B or their solutions can advantageously be useddirectly for preparing the copolymers according to the invention.However, they can also be initially purified or isolated. To do this,the compounds can, for example, be recrystallized from a suitablesolvent or precipitated with a precipitant. Examples of solvents of thistype are acetone, ethyl acetate, tert-butyl methyl ether andhydrocarbons.

An advantageous way of preparing the copolymers according to theinvention is precipitation polymerization in which the monomers aresoluble, but the polymer is insoluble, in the solvent system used.Suitable solvents are aromatic compounds such as toluene, xylene orhalogenated compounds such as 1,1,1-trichloroethane or methylenechloride, as well as semipolar solvents such as C₃-C₆ ketones orC₁-C₆-alkyl formates or acetates, also non-polar hydrocarbons, eg.cyclohexane or petroleum ether, and mixtures thereof. The polymer isobtained in the form of a fine-particle powder which is filtered off anddried in a suitable manner and, if required, finely ground.

Another polymerization technique is that of inverse emulsion orsuspension polymerization. In contrast to alkyl (meth)acrylates or otherlipophilic compounds, the cationic monomers B are at least partiallysoluble in water or mixtures of water with lower alcohols or ketones sothat the polymerization can be carried out very advantageously in thehydrophilic phase of a waterin-oil emulsion. The oil phase is chosen tobe a nonpolar liquid which is immiscible with water, such as ahydrocarbon, specifically liquid paraffin, or cyclohexane, as well ascosmetic oils. Protective colloids or emulsifiers are added to thesystem depending on required particle size of the product.

The free-radical polymerization is started by adding suitableinitiators, for example alkali metal or ammonium persulfates, hydrogenperoxide or azo initiators or azo or oxo initiators which are soluble inthe oil phase. Examples of the suitable initiator systems are diacylperoxide such as dilauroyl peroxide, didecanoyl peroxide, dioctanoylperoxide or dibenzoyl peroxide, peresters such as tert-butylperneodecanoate, tert-butyl perethylhexanoate, t-butyl perpivalate,tert-amyl perneodecanoate, t-amyl perethylhexanoate or tert-butylperisobutyrate or azo compounds such as2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile,dimethyl 2,2′-azobisisobutyrate or 2,2′-azobis(2-methylbutyronitrile).

The copolymers according to the invention are outstandingly suitable asthickeners or dispersants in industrial, pharmaceutical or, inparticular, cosmetic compositions. They are able to form thickened gelsand to stabilize emulsions permanently, as is required for cosmeticapplications in, for example, creams, lotions or gels.

The copolymers according to the invention are generally very suitablefor thickening aqueous systems such as suspensions of pigments in water,liquid detergents, aqueous polymer solutions and polymer dispersions.For this purpose, the polymer is adequately neutralized by adding a basesuch as triethanolamine, KOH, NaOH, 2-amino-2-methyl-1-propanol,2-amino-2-methyl-1,3-propanediol, diisopropanolamine ortetrahydroxypropylethylenediamine. The polymers can be used in a similarway for preparing very stable thickened emulsions from a water phase andan oil phase. The amounts of the polymer used to obtained permanentlystable emulsions are generally less than with conventional emulsifiers.

The present invention also relates to cosmetic compositions whichcontain the copolymers according to the invention as thickeners ordispersants in the amounts customary for this purpose, ie. about 0.05-2%by weight.

The copolymers according to the invention have a number of advantages:

The polymerization reaction for preparing them can, if required, becarried out in water because the cationic monomer B with a hydrophobicradical is at least partially soluble in water.

Particles in dispersed phases usually carry a negative charge(triboelectric effect). The cationic, amphiphilic groups in the polymertherefore have a good affinity for these phases. They are therefore ableto form stable emulsions on use of smaller amounts.

The introduction of cationic groups into an anionic polymer in thethickening state confer partial ampholytic characteristics on thelatter. This improves the electrolyte stability compared withconventional systems.

Cationic compounds have a high affinity for skin and hair. The emulsionsprepared with the copolymers according to the invention are thereforeparticularly suitable for cosmetics intended for the skin and hair.

EXAMPLES

Unless otherwise indicated, percentages are by weight.

Preparation of the Olefinically Unsaturated Quaternary AmmoniumCompounds B

Examples 1 TO 3

N-Dodecyl-N′-vinylimidazolium bromide (Example 1)

98 g of N-vinylimidazole and 258 g of dodecyl bromide were dissolved in500 ml of ethanol in a 2 l stirred vessel and stirred at 50° C. for 22h. The crude product was concentrated, taken up again in acetone andprecipitated by adding tert-butyl methyl ether. The isolated product wasdried under reduced pressure. The following were prepared in a similarway:

Methacryloyloxy(dimethyl)dodecylammonium Chloride (Example 2)N-Dodecyl-N′-vinylimidazolium Chloride (Example 3)

Examples 4 TO 8

N-Hexadecyl-N′-vinylimidazolium bromide (Example 4)

15 g of N-vinylimidazole and 50 g of 1-bromohexadecane were stirred in a500 ml vessel at 60° C. for 8 h. Then, 100 ml of ethyl acetate wereadded to this mixture while stirring. After a clear solution had formed,the heating and stirring was switched off. A colorless crystallineprecipitate formed during the cooling to room temperature and wasfiltered off and dried.

The following were prepared in a similar way:

Methacryloyloxyethyl(dimethyl)hexadecylammonium bromide (Example 5)

N-Octadecyl-N′-vinylimidazolium chloride (Example 6)

N-Benzyl-N′-vinylimidazolium chloride (Example 7)

Methacrylamidopropyl(dimethyl)hexadecylammonium chloride (Example 8)

Preparation of the copolymers according to the invention

Examples 9 TO 26 (precipitation polymers)

1000 ml of solvent, 200 g of acrylic acid, the comonomers andpentaerythritol triallyl ether as cross-linker were stirred in a 3 lflanged flask and flushed with nitrogen for 30 min. The mixture washeated to 80° C. while stirring under a stream of nitrogen, and whenthis temperature was reached a mixture of 80 ml of solvent and 0.3 g ofdilauroyl peroxide was added over the course of 3 h. After a further 4h, the mixture was cooled, and the precipitate part was filtered off,washed with solvent and dried. The starting materials and the amountsthereof are indicated in Table 1.

TABLE 1 Composition of the precipitation polymers Comonomers Ex.(Component B Pentaerythritol Solvent No. from Ex. No.) triallyl ether(ratio by vol.)  9 8.0 g 1 1.2 g 1,1,1-trichloroethane 10 8.0 g 2 1.2 g1,1,1-trichloroethane 11 2.4 g 1 1.0 g 1,1,1-trichloroethane 2.4 gstearyl methacrylate 12 4.0 g 4 1.2 g 1,1,1-trichloroethane 13 8.0 g 41.2 g acetone 14 8.0 g 4 1.2 g isopropyl acetate 15 5.0 g 6 1.2 g ethylacetate/cyclo- hexane (1:1) 16 5.0 g 7 1.2 g 1,1,1-trichloroethane 175.0 g 4 1.2 g ethyl acetate/cyclo- hexane (1:1) 18 2.5 g 4 0.8 g ethylacetate/cyclo- 2.5 g stearyl hexane (1:1) methacrylate 19 5.0 g 6 1.2 gethyl acetate/cyclo- hexane (1:1) 20 10.0 g 6 1.2 g cyclohexane 21 1.0 g4 1.2 g cyclohexane 5.0 g stearyl methacrylate 22 10.0 g 5 1.2 gisobutyl acetate 23 5.0 g 8 1.2 g ethyl acetate/cyclo- hexane (1:1) 2410.0 g 8 1.2 g ethyl acetate/cyclo- hexane (1:3) 25 4.0 g 4 0.6 g1,1,1-trichloroethane 26 4.0 g 4 0.3 g 1,1,1-trichloroethane

Comparative Example A

The reaction was carried out as in Examples 9 to 26 with 5.0 g ofstearyl methacrylate as sole comonomer and 1.2 g of pentaerythritoltriallyl ether in 1,1,1-trichloroethane.

Comparative example B

The reaction was carried out as in Examples 9 to 26 with 10.0 g ofstearyl methacrylate as sole comonomer and 1.2 g of pentaerythritoltriallyl ether in a mixture of ethyl acetate and cyclohexane in theratio 1:1 by volume.

Examples 27 TO 36

(Suspension polymers)

1000 ml of cyclohexane and a protective colloid or emulsifier wereintroduced into a 3 l flanged flask. After nitrogen had been passed infor 30 min, a mixture of 100 g water, 100 g of acrylic acid, 1 g ofpotassium peroxodisulfate and comonomers and, where appropriate,crosslinker was added dropwise while stirring at 75° C. over the courseof 30 min. After a further 3 h, the mixture was heated to boiling, andthe water was removed by azeotropic distillation. The remainingsuspension of the polymer was filtered off, washed with cyclohexane andthen dried under reduced pressure. The starting materials and theiramounts are indicated in Table 2.

TABLE 2 Composition of the suspension polymers Comonomers Ex. (ComponentB Protective colloid/ No. from Ex. No.) Crosslinker emulsifier 27 4.0 g1 — 2 g SMC 28 4.0 g 1 0.8 g diallyl- 3 g SMC tartaramide 29 33.0 gSPMAEDMA — 2 g SMC 5.3 g 1 30 4.0 g 1 — 2 g Dowfax 2A1 31 2.0 g 1 — 3 gDowfax 2A1 32 4.0 g 6 0.1 g bisacryl- 2 g Dowfax 2A1 amidoacetic acid 332.0 g 4 0.1 g polyethylene- 4 g of a technical glycol 200 bis- stearylalcohol acrylate with degree of ethoxylation n = 7 34 2.0 g 6 — 4 gDowfax 2A1 35 4.0 g 4 — 2 g Dowfax 2A1 36 2.0 g 4 0.1 g methylene- 2 gpolyvinyl- bisacrylamide pyrrolidone

SMC=styrene/maleic acid copolymer (90:10)SPMAEDMA=3-sulfopropylmethacryloyloxyethyldimethylammonium betaine

Dowfax 2A1=sodium salt of a disulfonic acid of an alkylated diphenylether.

Use properties

PREPARATION OF GELS

1.0 g of one of the polymers from Examples 9 to 36 and ComparativeExamples A and B was dispersed in 190 ml of water in a beaker. Whilestirring, 10 ml of a 10% strength triethanolamine solution were added.

The viscosity of the resulting gels was determined using a manualviscometer (Haake VT-02) (see Table 3 for results). The gels were thenspread on a glass plate to check the smooth texture by inspection.

The gels were made up as stated in water and in 1% strength NaClsolution. Comparison of viscosities of the two gels demonstrates thegreater salt stability of the partially ampholytic polymers according tothe invention (see Tab. 4 for results).

PREPARATION OF EMULSIONS

0.4 g of polymer was weighed into a beaker and dispersed in 30 ml ofliquid paraffin. Then 100 ml of water and subsequently 4 ml of a 10%strength triethanolamine solution were added while stirring vigorously.The emulsion was then homogenized with a disperser at 8000 rpm for a fews. The viscosity was determined as above (see Table 3 for results). Thelong-term stability was checked by examining the emulsion for any phaseseparation after standing in a 100 ml cylinder for 14 d.

TABLE 3 Viscosities of gels and emulsions Gel viscosity Emulsionviscosity Example No. [Pas] [Pas] Comp. Ex. A 12 9 Comp. Ex. B 5 4.3  98.5 6.2 10 4.5 6.4 11 13 13.9 12 20 19.8 13 16 10.2 14 9.2 7.8 15 10.18.8 16 - lump formation - — 17 18.0 11.1 18 6.3 3.9 19 7.5 11.0 20 4.16.4 21 12.5 11.7 22 14 12 23 9.2 13 24 12.1 9.6 25 15.2 14.1 26 10.8 1027 4.1 3.8^(a)) 28 - lump formation - — 29 3.9 4.8 30 5.2 4.7^(a)) 313.9 4.6 32 11.2 9.6 33 8.4 6.6 34 4.6 5.3 35 7.6 8.1 36 10.4 12^(a))slight oil separation after 14 h

TABLE 4 Comparison of the viscosities of the gels in water and in NaClsolution Viscosity in water/viscosity in Example No. 1% strength NaClsolution Comp. Ex. A 200 Comp. Ex. B 180 10 30 11 70 15 45 20 25 23 4025 60 29 50

The dispersibility of the polymers was checked by spreading the emulsionfrom Table 3 on a glass plate with a flat spatula and inspecting thethin film under a microscope. The following average particle sizes werefound:

Comparative Example A 30 μm

Example 10 8.5 μm

Example 13 20 μm

Example 18 15 μm

Example 19 6 μm

The smaller particle size of the emulsions obtained with the polymersaccording to the invention was an indicator of the improved emulsionstability of these phases.

We claim:
 1. A copolymer obtainable by free-radical polymerization of A)50-99.99% by weight of an olefinically unsaturated C₃-C₅ monocarboxylicacid, of an olefinically unsaturated C₄-C₈ dicarboxylic acid or theanhydride thereof or a mixture of such carboxylic acids or anhydrideswith B) 0.1-29.95% by weight of an olefinically unsaturated quaternaryammonium compound of the formula I or II

 where R¹ is C₆-C₂₀-alkyl, C₆-C₂₀-alkenyl, C₅-C₈-cycloalkyl, phenyl,phenyl(C₁-C₁₂-alkyl) or (C₁-C₁₂-alkyl)phenyl, R² is hydrogen, methyl orphenyl, R³ and R⁴ are each H or C₁-C₄-alkyl, X is halogen,C₁-C₄-alkoxysulfonyloxy or C₁-C₄-alkanesulfonate, it also being possiblefor the latter to occur as R³ or R⁴ with the formation of a betainestructure, Y is O or NH, and A is C₁-C₆-alkylene, or a mixture of suchammonium compounds, C) 0 to 49.99% by weight of an acrylate ormethacrylate of the formula III

 where R¹, R² and Y have the abovementioned meanings, R⁵ is hydrogen,methyl or ethyl, and n is a number from 0 to 25, D) 0-29.85% by weightof other copolymerizable monomers and E) 0.5-2% by weight of one or morecompounds with at least two olefinically unsaturated groups in themolecule as crosslinker.
 2. A copolymer as defined in claim 1, in whosepreparation acrylic acid, methacrylic acid or maleic anhydride has beenused as component A.
 3. A copolymer as defined in claim 1, in whosepreparation quaternary ammonium compounds I or II where R¹ isC₁₂-C₁₈-alkyl, C₁₂-C₁₈-alkenyl, or benzyl, R² is hydrogen, methyl orphenyl, R³ and R⁴ are each C₁-C₄-alkyl, X is chlorine, bromine,methoxysulfonyloxy, ethoxysulfonyloxy, methanesulfonate orethanesulfonate, Y is O or NH, and A is C₂-C₄-alkylene, have been usedas component B.
 4. A copolymer as defined in claim 1, in whosepreparation pentaerythritol triallyl ether, oleyl methacrylate,diallyltartaramide, bisacrylamidoacetic acid, methylenebisacrylamide ora polyethylene glycol di(meth)acrylate has been used as component E.